Terminals TB2-11 and TB2-12 are provided for ®eld in- stallation of a chilled water (¯uid) pump interlock (CWPI) and a chilled water (¯uid) ¯ow switch (CWFS). These de- vices are to be installed in series. Contacts must be rated for day circuit applications capable of handling a 24-vac to 50 mA load.
Accessory remote on-off switch can be wired into TB2-13 and TB2-14. To use this feature, remove the factory-installed jumper and install the device in series. See Fig. 13 for re- mote on-off, CWPI, and CWFS wiring. Contacts must be rated for dry load application capable of handling a 24-vac to 50 mA load.
Do not use interlocks or other safety device contacts connected between TB2 terminals 13 and 14 as remote on-off. Connection of safeties or other interlocks be- tween these 2 terminals will result in an electrical bypass if the REMOTE-OFF-LOCAL switch is in the LOCAL position. If remote on-off unit control is re- quired, a ®eld-supplied relay must be installed in the unit control box and wired as shown in Fig. 13. Failure to wire the remote on-off as recommended will result in tube freeze damage.
Terminals 2 and 3 of TB2 have been provided for a ®eld-supplied remote alarm (ALM). If an audible alarm is installed, an alarm shutoff is also recommended. Contacts are rated for 125 va at either 115 or 230 v control power. See Fig. 13.
Terminals 4 and 5 of TB2 have been provided for a ®eld-supplied chilled water (¯uid) pump relay (CWP). A ®eld-supplied power supply of appropriate voltage must be provided. Contacts are rated for 125 va at either 115 or 230 v control power. See Fig. 13.
Terminals 1 and 6 of TB2 have been provided for a ®eld-supplied control relay for the remote condenser (30HXA) or a condenser pump relay (30HXC). A ®eld-supplied power supply of appropriate voltage must be provided.
Step 5 Ð Install Accessories
ELECTRICAL Ð Several optional control accessories are available to provide the following features:
·control transformer
·cooler pump/¯ow switch interlock
·cooler pump control
·expanded display panel
·remote alarm
·remote on-off
·pulldown control
·occupancy scheduling
·demand limit control
·temperature reset (from occupied space or outdoor-air temperature)
·dual set point control
·condenser water sensors
·level II communications (CCN [Carrier Comfort Network])
Refer to Start-Up and Operation literature and sepa- rate accessory installation instructions for additional information.
30HXA LOW-AMBIENT OPERATION Ð If outdoor ambient operating temperatures below 60 F (15 C) are ex- pected, refer to separate installation instructions for low- ambient operation using accessory Motormaster III control.
MINIMUM LOAD ACCESSORY Ð If minimum load accessory is required, use the appropriate package. Refer to unit Price Pages or contact your local Carrier representative for more details. For installation details, refer to separate in- stallation instructions supplied with the accessory package.
MISCELLANEOUS ACCESSORIES Ð For applications re- quiring special accessories, the following packages are avail- able: control power transformer, minimum load control, sound reduction enclosure, external vibration isolation, expanded display, Victaulic-type connections, temperature reset sen- sor, and chilled ¯uid ¯ow switch. Refer to individual acces- sory installation instructions for installation details.
Step 6 Ð Leak Test Unit
30HXC UNIT Ð These units are shipped from the factory with a full charge of R-134a (See Tables 1A and 1B). Per- form a leak test to ensure that leaks have not developed during unit shipment. Dehydration of the system is not re- quired unless the entire refrigerant charge has been lost. There are a number of Swage-Lok ®ttings used on the refrigerant piping. If a leak is detected at any of these ®ttings, tighten outside nut 1¤8 turn.
DO NOT OVERTIGHTEN THESE FITTINGS. Over- tightening will result in the tube being crushed and will cause a refrigerant system leak.
30HXA UNITS Ð These units are shipped with a holding charge of R-134a. Leak test and dehydrate the complete sys- tem (including both ®eld and factory installed piping).
Step 7 Ð Refrigerant Charge
IMPORTANT: These units are designed for use with R-134a only. DO NOT USE ANY OTHER refrig- erant in these units without ®rst consulting your Carrier representative.
The liquid charging method is recommended for com- plete charging or when additional charge is required.
When charging, circulate water through the condens- er and cooler at all times to prevent freezing. Freezing damage is considered abuse and may void the Carrier warranty.
DO NOT OVERCHARGE system. Overcharging re- sults in higher discharge pressure with higher cooling ¯uid consumption, possible compressor damage, and higher power consumption.
